Feank southard



del.)

P. SOUTHARD.

MODE OF MANUFACTURING PEDAL OR ANKS FOR VELQGIPEDES. PatentedJam-211891..

NTTE STATES PATENT OEEIcE.

FRANK SOUTHARD, OF SOUTHAMPTON, ENGLAND.

MODE OF MANUFACTURING PEDAL-CRANKS FOR VELOCIPEDES.

SPEGIFIGATION forming part of Letters Patent No. 445,303, dated January2'7, 1891.

Application filed October 17, 1890. Serial No. 368,472. (No model.)Patented in England November 29, l888,1\l0. 17,408.

To all whom it may concern:

Be it known that I, FRANK SOUTHARD, residing at Southampton, England,have invented an Improved Method of Manufacturing Pedal-Cranks forVelociped es, (which has been patented to me in Great Britain under No.17,408, dated November 99, 1888,) of which the following is aspecification.

My invention relates to the treatment of the metal and the formation ofthe pedalcranks ot velocipedes, and has for its object the production ofa crank that shall be considerably lighter but as strong as those atpresent in use.

My improved cranks, as hereinafter fully described, are especiallyapplicable to light velocipedes wherein the consequent diminished weightof the cranks will be found to be at'urther advantage, especially in thecase of racing-machines.

My invention consists in twisting, the cranks so as to form spiralconvolntions.

I have found from my experiments that when a bar of metal is twisted asabove described, and when sufficiently heated, it is capable ofresisting torsional stress to a far greatereXtentth-an otherwise. Itiswellknown that the ordinary cranks of velocipedes have to be made of aconsiderable section in order to resist the torsional stress produced bythe pressure of the foot on the pedal.

In order that my invention may be the better understood,l now proceed todescribe the same in relation to the drawings hereunto annexed,reference being bad to the letters marked thereon.

Figure 1 shows a side view of an ordinary crank as at present in use.Fig. 2 is a view of a crank of reduced dimensions before twisting. Fig.3 is a view of the crank in Fig. 2

twisted according to my in\"ention. Fig.4 is a cross-section throughline A B in Fig. 3, showing the fluted contours of the convolutions;Figs. 5, 6, and 7 represent cranks having spiral convolutions ofdifferent pitches to suit various requirements. Figs. 8 and 9 illustratemy crank after the spiral ridges have been removed by turning orotherwise.

The twisting 0r spiraling may be imparted by means of any of the usualappliances, and preferably after the said cranks have been stamped outplain in the first instance of the reduced size, as shown in Fig. 2, andafter having been sufiiciently heated. The said cranks may be of anysuitable shape in cross-section such, for instance, as fluted,square,round, or other convenient form, may be desired. They maybe used just asleft after the twisting operation, or may be machined to any shape, asdesired.

My cranks, as above described, would be used in pairs-that is to say,the crank on the right-hand side of the machine would have right-handspiral convolutions and that on the left side left-hand spiralconvolutions.

What I claim, and desire to secure by Letters Patent of the UnitedStates, is

The method of manufacturing pedal-cran ks for velocipedes by twistingthem in their length to increase their strength, substantially asdescribed.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

FRANK SOUTHARD.

Witnesses:

CHARLES EDWARD KEELE,

Solicitor, Southampton. FREDK. ED ARDS, Capt. R. N., Gloucester Lodge,Southampton.

